Technical Field
The present invention relates to a light waveguide, a method of manufacturing the light waveguide, and a light waveguide device.
Related Art
In the related art, there are light waveguide devices configured to have light waveguides for transmitting light signals formed on wiring substrates for transmitting electric signals. The light waveguide devices are photoelectric substrates, and can transmit light signals at high-speed in order to compensate the transmission speed limitation of electric signals.
On end sides of the light waveguides, light path conversion mirrors are disposed, and optical elements are mounted on the wiring substrates so as to be optically coupled with the light path conversion mirrors of the light waveguides.    [Patent Document 1] Japanese Patent Application Publication No. 2002-267859    [Patent Document 2] Japanese Patent Application Publication No. 2007-94389
A light waveguide has a structure in which a core layer is surrounded by a lower cladding layer and an upper cladding layer, and the core layer is formed by patterning a photosensitive resin film on the basis of photolithography.
The cross section sizes of the core layers depend on the thicknesses of resin films, and the thickness limitation of resin films is about 10 μm. For this reason, it is difficult to form core layers having small cross section sizes in a range between 1 μm×1 μm and 3 μm×3 μm.
Therefore, it is impossible to easily meet the demand for manufacturing a light waveguide having a core layer having a difference in the cross section size between the light input side and the light output side.